SLP Vectorizer:  Add support for trees with external users.

To support this we have to insert 'extractelement' instructions to pick the right lane.
We had this functionality before but I removed it when we moved to the multi-block design because it was too complicated.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185230 91177308-0d34-0410-b5e6-96231b3b80d8
Replace UNIXy path with os-independent one in DebugIR unit test
- should resolve windows buildbot failure



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185232 91177308-0d34-0410-b5e6-96231b3b80d8
PPC: Ignore spill/restore requests for VRSAVE (except on Darwin)

This fixes PR16418, which reports that a function calling
__builtin_unwind_init() asserts. The cause is that this generates a
spill/restore for VRSAVE, and we support that only on Darwin (because VRSAVE is
only really used on Darwin).

The test case checks only that we don't crash. We can add correctness checks
once someone verifies what behavior the function is supposed to have.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185235 91177308-0d34-0410-b5e6-96231b3b80d8
Minimize precision loss when computing cyclic probabilities.

Allow block frequencies to exceed 32 bits by using the new
BlockFrequency division function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185236 91177308-0d34-0410-b5e6-96231b3b80d8
Try to unbreak Linux buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185237 91177308-0d34-0410-b5e6-96231b3b80d8